There are some methods to composite multiple vectors to one vector, they are:
(1) Concentrate them to one
For example, there are four 1*200 vectors, we will concentrate them to a 1*800 vector.
(2)Use self-attention method to get one vector
(3)Use mean pooling method
It means we will average four 1*200 vectors to get a 1*200 vector.
(4) Use max pooling method
Get the max value in four 1*200 vectors and get a 1*200 vector. We should notice, this method may better than self-attention method in some dataset.
Here is the full tutorial!